Brick for fireless cookers



E. Z. STOWELL.

BRICK FOR FIRELESS COOKERS.

APPLICATION FILED APR.1,1921- 1,412,717. Patented A r; 11, 1922,

2 s E 1 1 s 1 l Li Fig.2 5 1 Fig.1

[five min,

Elbriqge Z. S fiweU UNITED STATES PATENT OFFICE.

ELBBIDGE Z. STOWELL. 0F TUFTS COLLEGE, MASSACHUSETTS, ASSIGNOR 0 F TWO- FIFTHS TO WILLIAM F. MAGCORMACK, OF MALDEN, MASSACHUSETTS.

BRICK FOR FIRELESS COOKER/S.

Application filed April 1,

To all whom it may coacem:

Be it known that I, Ennmncn Z. STOWELL, a citizen of the United States, and a resident of Tufts College, in the county of Middlesex and Commonwealth of Massachusetts, have invented certain new and useful Improvements in Bricks for Fireless Cookers, of which the following is a full, clear, and exact specification.

In fireless cookers, as is well known, the heat for the baking and stewing is received from a hot object usually designated as a brick but in reality a block of soapstone, introduced within the non-conducting box. The main trouble found in connection with such blocks is their failure to give out heat at a sufiiciently high temperature and for a suflicientl long time to properly cook many kinds of cod.

The object of my invention is the production of a brick which shall overcome this objection and. will, therefore, continue to supply heat of a high temperature throu hout a period much in excess of what as previously been the case.

In accomplishing this, I take advantage. of the latent heat evolved during the change of a fluid to a solid, and thereby add materially to the heat emitted by the simple cooling of the body. The difficulty. however, is the discover of a substance which changes from solid to liquid at a temperature proper for cooking, but does not, on the other hand, vaporize at a temperature so low as to render such a process possible during the heating of the brick; for did such vaporizing occur, either the material would escape, or the receptacle be burst th ereby. Further, it must not decompose by frequent use, and, finally, it must not to be too expensive for" family After considerable study and experiment, I have discovered that a certain waste product resulting from the production of aniline dyes from coal-tar, termed phenanthrene, a hydrocarbon whose chemical formula is C H and which is graphically represented as fol ows:

1 l The melting point of this by-product is Specification of Letters Patent. Patented Apr. 11, 1922.

1921. Serial No. 457,669.

approximately 120 C., or about 248F., and consequently a good cooking temperature, so that after it has cooled down enough .to solidfy, it givesout a large amount of heat during the process. Further, this latent heat is far in excess of most other substances which might in some ways be available, and hence the material is ideal in this direction also.

The boiling point of this phenanthrene, moreover, is found to be approximately 330 C., and consequently at too high a temperature to be reached by a gas stove such as is used for heating fireless cooker bricks. It is in no danger, therefore, of vaporizing and causing loss of its own substance, or of exploding the container.

Inasmuch as this by-product possesses no other known value, but is a waste in the manufacture of certain aniline dyes, its cost is almost-nothing.

I have further found that continued heating and cooling of this phenanthrene fails to decompose it or otherwise render it unfit to perform its required function.

Since it liquefies at a comparatively low temperature-or only 36 F. above the boiling point of water,-it is necessary to confine it in a'fluid-tight jacket, as set forth in the accompanying drawings. in whichFig. 1 is a plan view of brick embodying my in vention, and Fig. 2 is aside sectional view of the same.

The jacket 1 is illustrated as circular to conform to the fireless. cookers now on the market, and is preferably composed of aluminum because of its lightness and noncorrosive nature, and more especially because of its high specific heat. To ensure the free conductivity of heat from the -material 4; to the exterior of the container 1,

ribs 5 reaching far into the material, and being of the same material aluminum, well adapted for the purpose.

The jacket 1 and its ribs 5 may be cast complete with a cover 6, an opening 2 closed. by a screw plug 3 being provided for the removal of the core used in the casting, and for pouring the material 4: therein.

The phenanthrene as it comes from the dye-works is a mass of flakes, but, by first heating it to its melting point, it can be poured into the jacket until full, and then the plug 3 screwed firmly in place.

What I claim is:

A brick for fireless cookers and the like, 1

comprising 'a jacket containing phenanthrene.

Intestimony that I claim the foregoing invention I have hereunto set my hand this 29th day of March, 1921.

ELBRIDGE Z. STOWELL. 

